Which Team Is Falling off Faster in Its Conference, the Thunder or the Celtics?

The Celtics and the Thunder faced major shakeups coming into this season.Elsa/Getty Images

Three weeks into a new NBA season and a few trends have begun to unfold.

One involves potential contenders adjusting to major personnel moves and how those moves may or may not affect their fates. And in examining that story line, the first two teams that come to mind are the Boston Celtics and the Oklahoma City Thunder.

Each of these two squads, who meet on Friday night in Boston, fell to the Miami Heat in last year's playoffs—the Celtics in the Eastern Conference Finals and the Thunder in the NBA Finals. And although the Celtics came closer to knocking off the eventual champs, the Thunder, thanks to their young, burgeoning core of superstars, looked like the group with more promise moving forward.

From the start of the offseason until the final hours of the preseason, both teams did some major retooling in the aftermath of their respective defeats. As you would expect, there have been growing pains.

The Celtics lost Ray Allen in free agency but otherwise went on a spending spree—not only re-signing Kevin Garnett, Brandon Bass and Jeff Green, but bringing in Jason Terry and trading for Courtney Lee.

The Thunder made far fewer moves but the biggest one they did make was arguably the biggest of the year and sent shock waves through the league.

Oklahoma traded James Harden, the reigning Sixth Man of the Year and third point in its young star triangle, to Houston. The centerpiece of Thunder's return on this move was 2-guard Kevin Martin, a very good offensive player in his own right, but not in the same class as Harden in terms of skill sets, overall talent and future potential.

Still, the Thunder are humming right along. The team sits at 9-3 through its first 12 games, giving them a healthy, early lead in the division and the second best winning percentage in the West. Oklahoma is only one game off its pace from last year and have essentially the same numbers in terms of both points scored and allowed per 100 possessions as in 2011-2012.

The Thunder still have issues in the front court especially in slowed down, half court situations given their lack of consistent offense from anyone not named Kevin Durant or Russell Westbrook. If they are to make a move in season, they may want to look for a big man who can score in the post, as Kendrick Perkins, Serge Ibaka and Nick Collison won't get it done in that regard.

But they've hardly fallen off. There's a long way to go, but the Thunder don't look like a team that will hit the postseason in much different shape as they did last year.

As for the Celtics (6-6), the situation in the early going is a bit more dicey. They got off to a slow start last year only to recover in time to make a scintillating playoff run which came one game short of another appearance in the Finals. A similar a fate is certainly possible for them this year too, but it's going to take a lot.

If you've watched the Celts play even for just a few minutes this season you'll see that they have serious issues attacking the boards. They managed just one offensive board in Wednesday night's loss to the Spurs, however, neither that nor their general deficiencies rebounding the ball are at the root of their problems.

What hurts the Celtics is their performance on defense, where they have gone from being one of the league's best to one of its worst over their first 12 games.

They've allowed 107 points per game in their six losses. So far they are tied for 25th of 30 teams in points allowed per 100 possessions. And, as Chris Forsberg of ESPN Boston pointed out on Wednesday following that 112-100 loss to San Antonio, they are near the bottom of the NBA in multiple defensive metrics as based on Synergy Sports models.

It hasn't helped the C's that there has been so much roster fluctuation. Again, plenty of new faces dot their roster and they are very guard heavy. This mitigates the losses of Allen and Avery Bradley (whose impending return will create even more of a logjam in the back court) but doesn't help their glaring needs up front, where Kevin Garnett is basically being asked to play two positions at once while having his minutes monitored at the same time.

Jeff Green, who isn't considered a "big man" but still checks in at 6'8" and can play the 4, hasn't really helped yet either. Save for a few isolated moments of aggression he is still, for the most part, the same passive, blank slate that he was when he came over from the Thunder at the 2010-2011 trade deadline.

In 22 minutes per night, Green is averaging a hugely disappointing 7.9 points and 2.8 rebounds. His player efficiency rating, as measured by ESPN.com's John Hollinger, is a putrid 9.8, better than only newcomer Courtney Lee's, who has also underachieved in a big way thus far.

The bottom line is that the Celtics, if they are truly going to contend, have to shore things up on the defensive end and try to figure out the enigma that is Green, who can't seem to shed any of the negative labels attached to him since being the fifth overall pick in the 2007 draft.

There are 70 games still left to play. It is far too early to make any truly sound judgments about much of anything yet. The Celtics were a game under .500 at the trade deadline last year and wound up one win away from the Finals. The Thunder looked like a team set to take a step back when they traded Harden but are currently as safe a bet as anyone in a wide open Western Conference.

So check back in a couple of months. The Celtics are clearly the team currently falling faster. But by then, we should have a much clearer picture of whether either of these two teams are really falling off.